[asterisk-users] How to stop ringing when incoming PSTN call is answered externally?

[Roger Burton West]

On Tue, May 22, 2012 at 11:32:19PM -0400, ftarz at mindspring.com wrote:
>The calls are routed just fine, but when a call is answered at one of
>the extensions or externally (by a home telephone) the asterisk
>extensions continue to ring one more time.  Is there a way to have
>Asterisk drop an incoming PSTN call as soon as it's answered?

I have the same problem, and earlier discussion here suggests it's
insoluble.